Class FakeListRemote

src/database/fakeListRemote.spec.ts:12–76

 * that accepts a JSON tree to serve upon construction.
 */
export class FakeListRemote implements ListRemote {
  data: any;
  delay: number;

  /**
   * @param data the fake database structure. Each leaf is an integer
   *   representing the subtree's size.
   */
  constructor(data: any) {
    this.data = data;
    this.delay = 0;
  }

  listPath(
    path: string,
    numChildren: number,
    startAfter?: string,
    timeout?: number,
  ): Promise<string[]> {
    if (timeout === 0) {
      return Promise.reject(new Error("timeout"));
    }
    const d = this.dataAtPath(path);
    if (d) {
      let keys = Object.keys(d);
      /*
       * We mirror a critical implementation detail of here. Namely, the
       * `startAfter` option (if it exists) is applied to the resulting key set
       * before the `limitToFirst` option.
       */
      if (startAfter) {
        keys = keys.filter((key) => key > startAfter);
      }
      keys = keys.slice(0, numChildren);
      return Promise.resolve(keys);
    }
    return Promise.resolve([]);
  }

  private size(data: any): number {
    if (typeof data === "number") {
      return data;
    }
    let size = 0;
    for (const key of Object.keys(data)) {
      size += this.size(data[key]);
    }
    return size;
  }

  private dataAtPath(path: string): any {
    const splitedPath = path.slice(1).split("/");
    let d = this.data;
    for (const p of splitedPath) {
      if (d && p !== "") {
        if (typeof d === "number") {
          d = null;
        } else {